The present invention relates to robot controls and more particularly to electronic robot controls in which microprocessors are employed in the implementation of servo control loops.
A robot control typically has capability for operating six robot axes, and each axis is typically provided with position and velocity control looping. In the case of a completely digital robot control like that set forth in this and the referenced patent applications, current control looping can also be included in the robot control.
In the implementation of a robot control with microprocessor technology, significant processing capability is thus required for servo loop control implementation in both hybrid digital/analog systems and completely digital systems. The required processing capability is based on general control requirements, data handling requirements and mathematical processing requirements.
The total capability requirement generally is not available in commercially available microprocessors. As a result, it has been the practice to employ multiple microprocessors in robot controls, with the microprocessors being assigned position and velocity and related control tasks on a per axis basis. One disadvantage associated with this design approach is that interactions among axes are not readily taken into account. Further, even with multiple microprocessors, there is limited capacity to accommodate more complex control algorithms which can be expected to be developed with continuing development of robot control technology.
Since no single microprocessor provides the features needed to satisfy the processing capability requirements for multi-axis robot control, it has been desirable that a new multi-microprocessor arrangement be devised provide improved microprocessor based robot control and to enable completely digital robot control to be achieved with high performance results, cost effectiveness and manufacturing economy. The present invention is directed generally to a multiprocessor servo control that can be embodied in different multiaxis robot control loops. Reference is made to U.S. Ser. No. 932,977 and U.S. Ser. No. 932,990 which are respectively related to a torque control embodiment and a position/velocity control embodiment. Reference is also made to U.S. Ser. No. 932,992 which is specifically related to an inter-processor communications interface employable in the multiprocessor servo control.